Electromagnetic reception and/or transmission is an important function of many devices such as for example, Cellular telephones, Personal Communications Systems (PCS) devices, Specialized Mobile Radios (SMR), Personal Digital Assistants, small computing devices with radio modems, Radio location devices, and the like. In addition, sound and light are important in the function of the sound and image recording capabilities of these devices i.e. digital camera functions, digital video image recording functions, sound/voice recording capabilities and the like. Commonly, when it is necessary to electromagnetically isolate such devices, the device or devices to be isolated are placed inside an enclosed space and a gasketed lid is securely latched thus creating a electromagnetic isolation (EMI) chamber. Such chambers are also known as “Faraday cages,” and may comprise a continuous shielding enclosure which prevents the ingress or egress of electromagnetic radiation.
Typically these types of chambers are used to isolate a single device for the purposes of testing, tuning and the repair of such devices. These devices can require that the device under test (DUT) be isolated from ambient electromagnetic radiation. Such a chamber may take the form of an entire room, known in the art as a “screen room” for its continuous screen shielding, or in the form of smaller shielded enclosures.
These enclosures are generally designed for devices under test, not necessarily for isolating active RF devices for security and privacy reasons. A shortcoming of at least some known shielding boxes is a lack of provision for the reduction of ambient sound and light, ungrounded operation and mobility.
The technology herein provides in one exemplary illustrative implementation, a portable ungrounded device capable of isolating such communication and recording devices. It is sometimes necessary to isolate such devices from transmitting or receiving any signals, communications and the such from outside of the protected space, thus containing or preventing the unwanted ingress and egress of information, data, images and the such from these devices to areas and or parties outside of the protected space, while remaining mobile and ungrounded.
Briefly described, the exemplary illustrative non-limiting apparatus comprises a box enclosing a volume which is fully shielded from electromagnetic radiation, shielded from sound and light for handling devices requiring electromagnetic isolation for reasons of security, privacy and the like. An exemplary illustrative non-limiting shielded enclosure comprises a structure having radio frequency (RF) shielding on or embedded in all sides or walls of the structure so that substantially no net electromagnetic radiation is transmitted either into or out of the structure. The structure is capable of providing attenuation (signal reduction) levels sufficient to render the device to be isolated inoperable and isolated to a degree that prevents the device from transmitting or receiving electromagnetic transmissions, signals, information, data, images, and the such from outside the protected space. The structure is openable, preferably by having a lid hinged from the body and securable by a latch or accessible or by other methods such as sliding lids, magnetic lids, swing out lids and the like, there being appropriately shielded by radio frequency gasketing between the lid and the body of the structure.
Additionally a sound resistant lining or barrier provides protection from the introduction of sound from outside of the chamber to recording devices inside the chamber. The structure may have a handle, handles and/or strap points in order to add to the mobility and usability of the device.
Secondary shielding may add ambient sound shielding and additional protection from ambient light. The chamber may also rely on the function of a Radio Frequency Absorbing Foam (RFAF) lining, and sound and light proof materials.